Analog delay lines are useful in many applications. For example, delay lines can be used in pulse shaping circuits which are typically used as an equalization method to account for losses and dispersion in transmission lines thus enabling higher data rates on the same lines. Delay lines can be used to simplify the circuits in many high speed digital signal processing applications such as radars and optical imaging (e.g., for removing stationary signals and monitoring only the changes in the image). Delay lines can also be used as a form of analog memory where the output is connected to the input through a transmission medium.
Typical delay lines are implemented using discrete components or electrical transmission lines. However, this results in a relatively large circuit if the delays required are long. Similarly, pulse shaping circuits which are required to significantly increase the duration of the pulse (e.g., to counteract dispersion in long transmission lines) would require relatively large circuits.